An industrial vehicle includes at least a structure 1 with the chassis 3 and a pair of crawler undercarriages 2 each of which is driven by a hydraulic motor 5 which transmits the motion and the engine torque to a planetary gear unit 6 on which is keyed a drive wheel 4. The hydraulic motor 5 and the reduction gear 6 are not directly connected, but between them is interposed a transmission device 10. During the detachment operation of the crawler undercarriage 2 from the chassis 3, the hydraulic motor 5 is released from the device of transmission 10 and remains attached to the chassis 3, preserving its hydraulic connections, while the planetary gear unit 6 and the transmission device 10 remain fixed to the undercarriage 2.